CES flat files, historical SIC series and vintage tables

Three BLS resources serve different historical employment questions. For machine-readable national Current Employment Statistics data, the CES access guide links to a flat-file directory and its ce.txt description. That description is the starting point for interpreting those files. [S1] For older Standard Industry Classification estimates, the same guide points to discontinued databases and SIC flat files. BLS states that SIC-based CES publishing ended after the April 2003 release and that those estimates are not compatible with later NAICS-based estimates. Do not silently splice the two classifications into one series. [S1] For changes to estimates of a particular reference month, use CES vintage tables. BLS describes these as published employment values for a given reference month across time. Historical B tables instead provide time series associated with Employment Situation tables. [S1] Before downloading, decide whether the question concerns an old classification, a historical table, or successive releases of the same month's estimate. Save the series identifier and documentation with the selected file. This selection checklist is editorial guidance.